<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>判断时间段</title>
		<script type="text/javascript">
			var time = prompt('what time is it now ?')
			if(time >= 23) {
				alert('夜已深')
			}else if (time >= 20) {
				alert('晚上好')
			}else if(time >= 15) {
				alert('傍晚好')
			}else {
				alert('中午好')
			}
		</script>
	</head>
	<body>
	</body>
</html>
